Riverside is experiencing its worst outbreak of Dutch elm disease since 2005, according to Village Forester Michael Collins. At the regularly scheduled meeting of the Riverside Landscape Advisory Commission on July 14, Collins reported that 80 elm trees on both public and private property had been removed.

Of that number, 46 elms were removed from the public right of way at a cost to the village of $35,670. The average trunk diameter size of the trees removed from public land this year is just under 26 inches.

The cost for removal of trees on private land is the responsibility of homeowners, which has made Collins an unpopular guy this summer.

If the village identifies an elm tree on private property that is showing signs of Dutch elm disease, Collins sends a letter to the homeowner alerting them that the tree needs to be removed.

Any tree with Dutch elm disease must be removed, according to a village ordinance, which is backed by state law. The same holds true for any tree infested by the emerald ash borer. So far, the ash borer has not been discovered in Riverside.

“I don’t enjoy doing it,” said Collins, who said that removal costs, depending on the size of the tree can be anywhere from $1,000 to $4,000.

The trees that have been removed to date began showing symptoms around June 16, Collins said.

According to Collins, Riverside has a total of 658 American and red elms, which are susceptible to Dutch elm disease, on parkways and in parks. The village also has 178 Siberian elms, which are resistant to the disease.

While there may be additional cases of Dutch elm in 2009, the village experiences its highest rates in June and July, Collins said.

“The removal of identified infected trees helps mitigate the severity of the second wave,” Collins said.

Dutch elm disease has also been bad in Brookfield in 2009, according to Village Forester Scott DeRoss. While the number of trees identified as having Dutch elm is much lower in Brookfield ¡ª around a half dozen or so ¡ª the village has far fewer American elm trees left on its parkways, which were originally planted with the trees by Brookfield’s founder Samuel Eberly Gross.

According to an article written by village historian Chris Stach in 2006, documents show that Gross in 1888 planted 10,000 trees, most of them elms, in what was to become Brookfield.

The village has fewer than 200 elm trees left standing, according to DeRoss.

“We don’t have too many left, and the larger, older American elms are being affected,” DeRoss said.

In addition, maple trees are being hit hard in Brookfield this summer, victims of fungal diseases such as verticillium wilt and anthracnose. The former disease spreads most easily in the drought conditions the area has felt in recent years. The latter favors long, cool, wet springs, such as the one we’ve just experienced.

“Verticillium wilt is the maple tree version of Dutch elm disease,” DeRoss said.

The future of an experimental tree planting program in Riverside is uncertain after members of the village’s Landscape Advisory Commission expressed skepticism about it at their meeting on July 14.

In both 2007 and 2008, the village’s forestry department has planted trees that are not on Riverside’s official list of species as part of a trial experiment funded by a private donation. In both years, Fairbank Road resident Steven Campbell donated $5,000 specifically to fund the plantings of Accolade elm and Marmo maple trees on public parkways.

In 2007, there were 13 Accolade elms and nine Marmo maples planted. Village Forester Michael Collins said he was unsatisfied with the maples, however, and in 2008 limited plantings to 19 Accolade elms.

When proposed in 2007, Jacquelyn Paine, then chair of the Landscape Advisory Commission, called the $5,000 donation the village’s largest ever and said that it was proposed to help control the loss of trees, such as American elms. Accolade elms are a hybrid species.

But John Kunka, who recently replaced Paine as chair of the commission, said last week that he prefers planting native species.

“The Accolade elm is not an American elm and we can’t delude ourselves into thinking we can replace the American elms, because you can’t.”

Kunka said that he would prefer seeking out native species that the village has not sought out.

“There are other species available if we make the effort,” Kunka said.

Eric Zuschlag, also appointed recently to the commission, backed Kunka, saying, “I am not a fan of giving up on native species and replacing them with non-native ones.”

Commissioner Bob Finn, on the other hand, showed some support for the experimental program, saying that it doesn’t cost the village anything and provides a diverse tree stock.

“Down the line it will help,” Finn said.

Campbell also spoke at the meeting, saying he funded the program in response to such blights as the Gypsy moth and emerald ash borer.

“Who of us could have envisioned the losses we’ve had?” he asked, adding “I fail to see how three or four trees of different species will jeopardize the Olmstedian vision.”

To Kunka, he added, “If you think it’s that harmful to the ongoing ideals of Riverside, feel free to reject the donation.”

Landscape Advisory Commission members did not reject the offer, but asked Collins to develop a list of tree species for the commission to consider. The commission is expected to vote on extending or ending the program at its Aug. 4 meeting.